I'm using that cooler on my Duron 800. It's the Molex brand (you can check it out at
www.molex.com and actually order from a US dealer, if you want).
According to Glenn from QuietPC.com the fan is rated to Thunderbird 1 GHz.
Since you're not OC'ing, I recommend you to get this product. Especially if you get irritated by noise like I do, you'll love it. However, it's not the most efficient cooler out there.